clustermesh: propagate synchronization info in remote cluster status

Enrich the remote cluster status to additionally include information
concerning the synchronization status of each resource type. In
particular, a resource type is considered to be synchronized if the
initial list of entries has been completely received from the remote
cluster, and new events are currently being watched.

Signed-off-by: Marco Iorio <marco.iorio@isovalent.com>

api/v1/openapi.yaml

@@ -2379,6 +2379,9 @@ definitions:
       ready:
         description: Indicates readiness of the remote cluster
         type: boolean
+      synced:
+        description: Synchronization status about each resource type
+        "$ref": "#/definitions/RemoteClusterSynced"
       config:
         description: Cluster configuration exposed by the remote cluster
         "$ref": "#/definitions/RemoteClusterConfig"
@@ -2404,6 +2407,27 @@ definitions:
         description: Time of last failure that occurred while attempting to reach the cluster
         type: string
         format: date-time
+  RemoteClusterSynced:
+    description: |-
+      Status of the synchronization with the remote cluster, about each resource
+      type. A given resource is considered to be synchronized if the initial
+      list of entries has been completely received from the remote cluster, and
+      new events are currently being watched.
+
+      +k8s:deepcopy-gen=true
+    properties:
+      nodes:
+        description: Nodes synchronization status
+        type: boolean
+      services:
+        description: Services synchronization status
+        type: boolean
+      endpoints:
+        description: Endpoints synchronization status
+        type: boolean
+      identities:
+        description: Identities synchronization status
+        type: boolean
   RemoteClusterConfig:
     description: |-
       Cluster configuration exposed by the remote cluster

pkg/client/client.go

@@ -404,6 +404,11 @@ func FormatStatusResponse(w io.Writer, sr *models.StatusResponse, sd StatusDetai
 					fmt.Fprint(w, "expected=unknown, retrieved=unknown")
 				}
 				fmt.Fprint(w, "\n")
+
+				if cluster.Synced != nil {
+					fmt.Fprintf(w, "   └  synchronization status: nodes=%v, endpoints=%v, identities=%v, services=%v\n",
+						cluster.Synced.Nodes, cluster.Synced.Endpoints, cluster.Synced.Identities, cluster.Synced.Services)
+				}
 			}
 		}
 	}

pkg/clustermesh/remote_cluster.go

@@ -150,6 +150,14 @@ func (rc *remoteCluster) Status() *models.RemoteCluster {
 	status.NumSharedServices = int64(rc.remoteServices.NumEntries())
 	status.NumIdentities = int64(rc.remoteIdentityCache.NumEntries())
 	status.NumEndpoints = int64(rc.ipCacheWatcher.NumEntries())
+
+	status.Synced = &models.RemoteClusterSynced{
+		Nodes:      rc.remoteNodes.Synced(),
+		Services:   rc.remoteServices.Synced(),
+		Identities: rc.remoteIdentityCache.Synced(),
+		Endpoints:  rc.ipCacheWatcher.Synced(),
+	}
+
 	return status
 }